This is the sixth time since the dawn of the 21st century that at least five different teams have been ranked No.1. The 2003-04 season holds the millennial record for most top-spot diversity with six teams.

What does it all mean?

That the 2012-13 season has been about as nutty as we all thought it was. And that we have plenty to discuss in the latest installment of W/L's: AP Poll Edition.

Winner: Gonzaga

William Mancebo/Getty Images

Last Week: 2nd

This Week: 1st

Record: 29-2, 16-0 (WCC)

How could we start anywhere else?

With wins in its final two conference games, Gonzaga lands the program's first-ever No. 1 ranking. It's a tremendous accomplishment not only for the Bulldogs, but for small-school basketball programs everywhere, many of whom have spent the past decade slowly reemerging from under the crush of power-conference alignment. All that as subtext, Gonzaga's No.1 belongs right alongside the Final Four seasons of VCU, Butler and George Mason in the pantheon of mid-major accomplishment.

By the way, last time we saw a school achieve its first-ever No.1 ranking?

Winner: Duke

Rarely does a Top Five team lose and hold its poll position. Even rarer is a Top Five team that loses and actually gains five first-place votes.

But this was no normal week for the Blue Devils, who lost to Virginia on Thursday without Ryan Kelly but then bounced back for a high-profile win against Miami—this with with the 6'11" senior in the lineup.

It helped that Kelly scored 36 points against the 'Canes, providing a clear before-and-after tableau for voters who'd rather disregard Duke's play during Kelly's absence.

Loser: Arizona

Stephen Dunn/Getty Images

Last Week: 11th

This Week: 18th

Record: 23-6, 11-6 (Pac-12)

Back-to-back road losses in L.A. sent Arizona to its lowest ranking of the season.

And while the belly-flop at USC was embarrassing, let's remember that the Wildcats went undefeated through the nation's 19th-toughest nonconference schedule and have wins over Florida, Miami, San Diego State, Colorado and Arizona State.

Winner: UCLA

Stephen Dunn/Getty Images

Last Week: NR (No Votes)

This Week: 23rd

Record: 22-7, 12-4 (Pac-12)

Oh the joys of being a blue blood.

Despite not receiving a single vote last week, UCLA shot past a slew of poll hopefuls and into the Top 25 on the strength of two close home wins. Sure, one of them came against Arizona, but you saw the previous slide—the Wildcats haven't exactly set the world on fire of late.

But it's typical to see teams with high preseason expectations and loads of blue-chip talent pick up quick momentum, and Ben Howland's Bruins have ridden the wave to their first Top 25 ranking since mid-January.

Loser: Louisiana Tech

Jennifer Stewart-USA TODAY Sports

Last Week: 25th

This Week: NR (27th)

Record: 26-3, 16-0 (WAC)

Louisiana Tech's first foray into the Top 25 since 1985 was a short one.

The Bulldogs won two home games last week—each by more than 20—but fell two spots anyway amid other turbulence. And an important two spots they were for a program that hasn't enjoyed much national attention since the bygone Karl Malone days.

On the bright side, tough road games against New Mexico State and Denver give Louisiana Tech two more opportunities to impress the voters—that is assuming they actually pay attention to the mid-major conferences.

Winner: Oregon

For the Ducks, it was one of those weeks where everything around them broke right.

Arizona lost twice, giving them dual possession of first place in the Pac-12 alongside UCLA. Other fringe Top 25 teams like Notre Dame, Wisconsin, Memphis and Butler all lost.

And even though a 10-point home win is nothing to crow about, Oregon shot up five spots, cracking the Top 20 for the first time since Feb. 4.

Note on Marquette: The Golden Eagles are certainly worthy of recognition after moving from 22nd to 15th this week. I just don't think their ranking is all that notable. They earned the jump, beating two ranked foes.

Loser: Middle Tennessee State

Jim Brown-USA TODAY Sports

Last Week: NR (36th)

This Week: NR (35th)

Record: 27-4, 19-1 (Sun Belt)

With Akron losing, I thought Middle Tennessee State might start to feel some of the mid-major love. Instead, it seems Power Six risers like UCLA and North Carolina picked up the loose change, while the Blue Raiders, winners of 16 straight, were left idling at the back of the "Others receiving votes" queue.

RPI says MTSU is one of the country's top-25 teams. Voters, apparently, beg to differ.